Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
A number of scientific methods have been developed in the medical field to evaluate a person's health state. A person's health state may, for example, be evaluated based on the measurement of one or more physiological parameters, such as blood pressure, pulse rate, skin temperature, or galvanic skin response (GSR). In a typical scenario, these measurements may be taken in the home or a health-care setting by using several discreet devices or sensors and, in some cases, by drawing blood or other bodily fluid. For most people, the measurements or blood tests are performed infrequently, and changes in a physiological parameter, which may be relevant to health state, may not be identified, if at all, until the next measurement is performed.
In another example, these parameters may be more frequently or continuously measured, and other health-related information obtained, by a wearable device. The device, which may be provided as a wrist-mounted device, may include one or more sensors for detecting or measuring one or more physiological parameters. For example, a wrist-mounted device may include optical sensors for heart rate and blood oxygen saturation (SpO2) monitoring, a thermistor for measuring skin temperature, and a GSR sensor for measuring skin resistance. At least some of the physiological parameter information may be obtained by detecting the presence, absence and/or concentration of one or more analytes in the body.
Calibration and testing of such wearable devices can be important to ensure that the sensors on the device function properly and accurately. In some cases, calibration and testing may be performed by mounting the device on the wrist (or other body surface) of a human subject. However, using a living subject, it is difficult to control or create all of the necessary conditions or ranges to properly test the device. Further, repeatability of testing conditions may also be very difficult to achieve using a living subject. In another example, a simulator device may be used to calibrate and test a wearable device. Currently available simulators are designed to test and calibrate fingertip heart rate and SpO2 measurement devices which operate by measuring the transmission of light through a person's fingertip. These simulators operate by intercepting the light emitted from the emission side of a fingertip monitoring device and replacing it with its own signal, which is received on the detection side of the monitoring device. However, this simulator is not capable of calibrating or testing monitoring devices utilizing reflective sensors. Further, these known simulators are specifically designed to test fingertip monitoring devices and are, therefore, not in the right form for testing a wrist-mounted device.